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Discovering the causes of cancer and the means of prevention


A cohort is a defined population observed over time, either prospectively or retrospectively. In some cohorts, members share a characteristic such as an occupational exposure or medical condition, while some other cohorts are samples of the general population. In addition, some DCEG cohorts were first enrolled in clinical or prevention trials, but continue to be followed as a general population cohort.

Cohort members are often surveyed to gather information on lifestyle factors such as diet and nutrition, exercise, use of alcohol or tobacco, because these factors can be related to cancer risk. They are followed over time to gather updates on their general health. In addition, in some studies, members agree to donate biospecimens such as blood, buccal cell, and urine.

For cancer studies that require large numbers of subjects and biospecimens, DCEG investigators often participate in large consortia (collaborative partnerships) that pool data and biospecimens across numerous cohorts. For example, the NCI Cohort Consortium includes investigators responsible for more than 40 high-quality cohorts, involving more than 4 million people.

Following are examples of DCEG cohort studies:

General population cohorts

Alpha-Tocopheral Beta-Carotene Cancer Prevention (ATBC) Study
Connect for Cancer Prevention Study
NIH-AARP Diet and Health Study
Prostate, Lung, Colon, and Ovarian (PLCO) Cancer Study
Shanghai Women’s Health Study

Occupational cohorts

Agricultural Health Study
Benzene-Exposed Workers in China
Cohort Mortality Study of Dry Cleaning Industry Workers
Cohort Mortality Study of Philadelphia Firefighters
Diesel Exhaust in Miners Study
Interventional Fluoroscopists
NCI Acrylonite Cohort
U.S. Radiologic Technologists

Environmental Exposure Cohorts

Thyroid Disease in Young Persons Exposed Near Chernobyl
Methodologic Studies of Radioactive Fallout

Medical Conditions or Treatment Cohorts

Childhood Cancer Survivors
DES Follow-up Study
Follow-up Study of Women in the Fracture Intervention Trial
HPV Vaccine Study in Costa Rica
NCI International EBV-Gastric Cancer Consortium
Nutritional Intervention Trials in Linxian, China
Retinoblastoma Survivors Follow-up Study
PRIMAVERA*-ESCUDDO Trial to Compare One Dose of Bivalent HPV Vaccine to Three Doses of Quadrivalent Vaccine
Second Primary Gastrointestinal Cancers
Scientific Evaluation of One or Two Doses of the Bivalent or Nonavalent Prophylactic HPV Vaccines—The ESCUDDO* Study
Study of Women Evaluated and Treated for Infertility